Oil field chemical release system

Abstract

An oil field chemical release system for controlled release of an oil field chemical within a hydrocarbon reservoir, well, or wellbore, the oil field chemical release system comprising: a plurality of microcapsules, each microcapsule comprising an oil field chemical and a microencapsulant, wherein the oil field chemical is contained within the microencapsulant; and a continuous bulk polymer matrix, wherein the plurality of microcapsules are disposed within the continuous bulk polymer matrix, wherein the oil field chemical release system is configured to allow the oil field chemical to move through the microencapsulant into the continuous bulk polymer matrix and through the continuous bulk polymer matrix to be released through a surface of the bulk polymer matrix into the hydrocarbon reservoir, well, or wellbore at a controlled rate, and wherein the oil field chemical release system is configured to provide a release profile.

The invention claimed is: 
     
       1. An oil field chemical release system for controlled release of an oil field chemical within a hydrocarbon reservoir, well, or wellbore, the oil field chemical release system comprising:
 a plurality of microcapsules, each microcapsule comprising an oil field chemical and a microencapsulant, wherein the oil field chemical is contained within the microencapsulant; and 
 a continuous bulk polymer matrix, wherein the plurality of microcapsules are disposed within the continuous bulk polymer matrix, 
 wherein the oil field chemical release system is configured to allow the oil field chemical to move through the microencapsulant into the continuous bulk polymer matrix and through the continuous bulk polymer matrix to be released through a surface of the bulk polymer matrix into the hydrocarbon reservoir, well, or wellbore at a controlled rate, 
 wherein the oil field chemical release system is configured to provide a release profile, calculated as a weight percentage of an initial oil field chemical content of the chemical release system, in a range 0.01 to 8.3 wt % per month for a time period of at least 1 year at a target temperature in a range −45° C. to 300° C., 
 wherein the continuous bulk polymer matrix is an epoxy resin system comprising at least two different epoxy monomers which are chemically bonded to form a co-polymer, 
 wherein the microencapsulant comprises a co-polymer formed of at least two different monomers which are chemically bonded to form the co-polymer, and 
 wherein the at least two different epoxy monomers in the epoxy resin system comprise at least two different epoxy ether monomers. 
 
     
     
       2. The oil field chemical release system according to  claim 1 , wherein the release profile of the oil field chemical is in a range 0.01 to 4.2 wt % per month for a time period of at least 2 years. 
     
     
       3. The oil field chemical release system according to  claim 1 , wherein the release profile of the oil field chemical is in a range 0.01 to 2.8 wt % per month for a time period of at least 3 years. 
     
     
       4. The oil field chemical release system according to  claim 1 , wherein the release profile of the oil field chemical is in a range 0.01 to 1.7 wt % per month for a time period of at least 5 years. 
     
     
       5. The oil field chemical release system according to  claim 1 , wherein the release profile of the oil field chemical is in a range 0.01 to 1.2 wt % per month for a time period of at least 7 years. 
     
     
       6. The oil field chemical release system according to  claim 1 , wherein the release profile of the oil field chemical is in a range 0.01 to 0.8 wt % per month for a time period of at least 10 years. 
     
     
       7. The oil field chemical release system according  claim 1 , wherein the release profile of the oil field chemical is at least 0.05, 0.1, 0.2, 0.5, 0.7, or 0.8 wt % per month. 
     
     
       8. The oil field chemical release system according to  claim 1 , wherein the target temperature is in a range 0° C. to 250° C., 20° C. to 200° C., 50° C. to 150° C., 60° C. to 120° C., or one of 60° C., 90° C., or 120° C. 
     
     
       9. The oil field chemical release system according to  claim 1 , wherein the epoxy resin system further comprises a curing or cross-linking agent. 
     
     
       10. The oil field chemical release system according to  claim 1 , wherein the microcapsules have a diameter of from 50 nm to 2 mm. 
     
     
       11. The oil field chemical release system according to  claim 1 , wherein the oil field chemical is a tracer. 
     
     
       12. The oil field chemical release system according to  claim 1 , wherein the oil field chemical has a melting point of less than 250° C. 
     
     
       13. The oil field chemical release system according to  claim 1 , wherein the oil field chemical has a melting point in a range 100 to 250° C. 
     
     
       14. Use of the oil field chemical release system according to  claim 1  to release an oil field chemical within a hydrocarbon reservoir, well, or wellbore. 
     
     
       15. A set of oil field chemical release systems according to  claim 1 , wherein one of the oil field chemical release systems is configured to provide the release profile at a first target temperature and another of the oil field chemical release systems is configured to provide the release profile at second target temperature which is different to the first target temperature. 
     
     
       16. The set of oil field chemical release systems according to  claim 15 , comprising at least three oil field chemical release systems, one configured to provide the release profile at 60° C., another to provide the release profile at 90° C., and another to provide the release profile at 120° C. 
     
     
       17. The oil field chemical release system of  claim 1 , wherein one epoxy monomer of the at least two different epoxy monomers contains two epoxy groups and a second epoxy monomer contains one epoxy group.